About this issue, we need to do the cross-checking to confirm the root cause.
1. Plug the USB drive into another USB port on the TV.
2. Change another USB drive and insert it into the USB port, and then check the video quality on the TV.
3. Unplug the video source devices from the HDMI ports or the AV port or the satellite input ports, so we could confirm whether the interference causes the issue.
4. Try to restore the TV back to the factory settings: press the Home button and select SettingsDevice PreferencesFactory Reset.
5. If the TV has internet access, please check if there is a new version of software updated online or not.
Press the Home button on the TV remote, and select SettingsDevice PreferencesAboutSystem updateNetwork Update:

If the issue cannot be resolved, please feel free to call the TCL hotline for further help.